1. Field of the Invention
The present invention relates to a crushing system typically consisting of a self-propelled crushing machine.
2. Description of Related Art
Conventionally, a self-propelled crushing machine is known as a crushing system. Such self-propelled crushing machine is normally systematized and adapted to operate selectively in a traveling mode for moving on lower traveling bodies, in a single operation mode where one of the operation units (grizzly feeder, crusher, delivery conveyor, etc.) to be driven and stopped alone or in an interlocked operation mode where the respective operation units are driven and stopped in a predetermined order in an interlocked manner. For operation, one of the modes is selected by a mode selection switch. (See FIGS. 7, 8 and 9 of Japanese Patent Laid-Open Publication No. Hei11-156226)
In such a system, when the interlocked operation mode is selected and an interlocked operation ON switch is pressed for a series of steps of crushing cycle, the operation units are sequentially driven to start operating with predetermined time lags from the operation unit arranged at the most downstam side, whereas the operation units are sequentially stopped with predetermined time lags from the operation unit arranged at the most upstream side when an interlocked operation OFF switch is pressed.
For instance, where a grizzly feeder, a crusher, a delivery conveyor and the like are sequentially arranged from upstream to downstream the delivery conveyor is driven to operate first and stopped last when the interlocked operation mode is selected for a crushing operation. Therefore, the crushed material crushed by the crusher would not be sent to the delivery conveyor is not driven and hence the narrow space etc. between the crusher and the delivery conveyor would normally be prevented from being clogged by the crushed material.
However, when the system disclosed in the above-described prior art is operated in an interlocked operation mode and then stopped (a situation to be also referred to as interlocked operation stop or interlocked operation OFF hereinafter), the crusher and the delivery conveyor are sequentially stopped at predetermined time intervals after the most upstream grizzly feeder is stopped. Thus, if a raw material such as natural stones that are hard and can be crushed only with large force is put into the crusher, the raw material may remain, if partly, in the crusher even when the time comes for stopping the crusher. Then, if the crusher is actually stopped under the condition, the delivery conveyor can be stopped before the crushed material is completely delivered to the outside.
In such a situation, the raw material is left in the crusher, and the crushed material remains on the delivery conveyor in an area immediately below the crusher so that the single operation mode needs to be selected to respectively drive the crusher and then the delivery conveyor to remove the crushed material when the crusher and the periphery of the crusher is inspected and an outlet port of the crusher is dimensionally regulated. It is a time consuming operation to remove the crushed material remaining there.